This invention relates to control apparatus for pumping oil wells and more particularly involves flow detection means to be used in the flowlines of pumped oil wells to indicate when fluid is being produced from the pumped well.
In an oil well pumpoff control system such as that disclosed in U.S. Pat. No. 3,854,846 and U.S. Pat. Applications Ser. No. 452,851 now U.S. Pat. No. 3,946,462; Ser. No. 469,264 now U.S. Pat. No. 3,938,910; Ser. No. 519,904; and Ser. No. 520,993 now U.S. Pat. No. 3,936,231, all assigned to the assignee of this invention, means are required for determining when the oil well pump is performing efficiently. This involves many methods, such as measuring the level of fluid in the well bore, measuring the load on the walking beam by strain gauge, measuring the amperage on the prime mover power supply, measuring the amperage drawn by electric submersible pump, and by sensing the production of fluid through the well flowline.
Many of these sensing devices suffer from the disadvantages of over-complexity, inability to detect pump failure, and inclination to become stopped up or fouled by sediment, paraffin and/or sand carried by the produced well fluid.
The present invention overcomes these difficulties by providing a packaged sensing unit that can be quickly and simply inserted in the well flowline and which exhibits extended reliability and resistance to fouling.
The entire application, Ser. No. 469,264, entitled "OIL WELL PUMPOFF CONTROL SYSTEM UTILIZING INTEGRATION TIMER" by Bobby L. Douglas, filed May 13, 1974 now U.S. Pat. No. 3,938,910, is herein incorporated by reference.